The formation of ultra-compact dwarf galaxies and nucleated dwarf galaxies

Ultra compact dwarf galaxies (UCDs) have similar properties as massive globular clusters or the nuclei of nucleated galaxies. Recent observations suggesting a high dark matter content and a steep spatial distribution within groups and clusters provide new clues as to their origins. We perform high-resolution N-body / smoothed particle hydrodynamics simulations designed to elucidate two possible formation mechanisms for these systems: the merging of globular clusters in the centre of a dark matter halo, or the massively stripped remnant of a nucleated galaxy. Both models produce density profiles as well as the half light radii that can fit the observational constraints. However, we show that the first scenario results to UCDs that are underluminous and contain no dark matter. This is because the sinking process ejects most of the dark matter particles from the halo centre. Stripped nuclei give a more promising explanation, especially if the nuclei form via the sinking of gas, funneled down inner galactic bars, since this process enhances the central dark matter content. Even when the entire disk is tidally stripped away, the nucleus stays intact and can remain dark matter dominated even after severe stripping. Total galaxy disruption beyond the nuclei only occurs on certain orbits and depends on the amount of dissipation during nuclei formation. By comparing the total disruption of CDM subhaloes in a cluster potential we demonstrate that this model also leads to the observed spatial distribution of UCDs which can be tested in more detail with larger data sets.Comment: 8 pages, 8 figures, final version accepted for publication in MNRA

Smokers’ and drinkers’ choice of smartphone applications and expectations of engagement: a think aloud and interview study

BACKGROUND: Public health organisations such as the National Health Service in the United Kingdom and the National Institutes of Health in the United States provide access to online libraries of publicly endorsed smartphone applications (apps); however, there is little evidence that users rely on this guidance. Rather, one of the most common methods of finding new apps is to search an online store. As hundreds of smoking cessation and alcohol-related apps are currently available on the market, smokers and drinkers must actively choose which app to download prior to engaging with it. The influences on this choice are yet to be identified. This study aimed to investigate 1) design features that shape users’ choice of smoking cessation or alcohol reduction apps, and 2) design features judged to be important for engagement. METHODS: Adult smokers (n = 10) and drinkers (n = 10) interested in using an app to quit/cut down were asked to search an online store to identify and explore a smoking cessation or alcohol reduction app of their choice whilst thinking aloud. Semi-structured interview techniques were used to allow participants to elaborate on their statements. An interpretivist theoretical framework informed the analysis. Verbal reports were audio recorded, transcribed verbatim and analysed using inductive thematic analysis. RESULTS: Participants chose apps based on their immediate look and feel, quality as judged by others’ ratings and brand recognition (‘social proof’), and titles judged to be realistic and relevant. Monitoring and feedback, goal setting, rewards and prompts were identified as important for engagement, fostering motivation and autonomy. Tailoring of content, a non-judgmental communication style, privacy and accuracy were viewed as important for engagement, fostering a sense of personal relevance and trust. Sharing progress on social media and the use of craving management techniques in social settings were judged not to be engaging because of concerns about others’ negative reactions. CONCLUSIONS: Choice of a smoking cessation or alcohol reduction app may be influenced by its immediate look and feel, ‘social proof’ and titles that appear realistic. Design features that enhance motivation, autonomy, personal relevance and credibility may be important for engagement

Worry and behaviour at the start of the COVID-19 outbreak: results from three UK surveys (the COVID-19 Rapid Survey of Adherence to Interventions and Responses [CORSAIR] study)

We aimed to describe worry and uptake of behaviours that prevent the spread of infection (respiratory and hand hygiene, distancing) in the UK at the start of the COVID-19 outbreak (January and February 2020) and to investigate factors associated with worry and adopting protective behaviours. Three cross-sectional online surveys of UK adults (28 to 30 January, n=2016; 3 to 6 February, n=2002; 10 to 13 February 2020, n=2006) were conducted. We used logistic regressions to investigate associations between outcome measures (worry, respiratory and hand hygiene behaviour, distancing behaviour) and explanatory variables. 19.8% of participants (95% CI 18.8% to 20.8%) were very or extremely worried about COVID-19. People from minoritized ethnic groups were particularly likely to feel worried. 39.9% of participants (95% CI 37.7% to 42.0%) had completed one or more hand or respiratory hygiene behaviours more than usual in the last seven days. Uptake was associated with greater worry, perceived effectiveness of individual behaviours, self-efficacy for engaging in them, and having received more information. 13.7% (95% CI 12.2% to 15.2%) had reduced the number of people they had met. This was associated with greater worry, perceived effectiveness, and self-efficacy. At the start of novel infectious disease outbreaks, communications should emphasise perceived effectiveness of behaviours and ease with which they can be carried out

Can health trainers make a difference with difficult-to-engage clients? A multisite case study

A political attempt in the United Kingdom to address health inequalities in the past decade has been the government’s initiative to employ local health trainers (HTs) or health trainer champions (HTCs) to support disadvantaged individuals with aspects of their health-related behaviors. HT/HTCs provide health-related information and support to individuals with healthy eating, physical activity, and smoking cessation. They undertake community engagement and direct individuals to relevant health services. They differ in that HTs are trained to provide health interventions to individuals or groups and to make referrals to specialist health care services when necessary. This article provides an evaluation of HT/HTCs interventions across three sites, including one prison, one probation service (three teams), and one mental health center. An evaluation framework combining process and outcome measures was employed that used mixed methods to capture data relating to the implementation of the service, including the context of the HT/HTCs interventions, the reactions of their clients, and the outcomes reported. It was found that HT/HTCs interventions were more effective in the prison and mental health center compared with the probation site largely as a result of contextual factors

Obesity prevention in the early years: a mapping study of national policies in England from a behavioural science perspective

Background Evidence indicates that early life is critical for determining future obesity risk. A sharper policy focus on pregnancy and early childhood could help improve obesity prevention efforts. This study aimed to systematically identify and categorise policy levers used in England with potential to influence early lifecourse (pregnancy, 0-5 years) and identify how these interface with energy balance behaviours. The objective is to identify gaps and where further policy actions could most effectively focus. Methods A behavioural science approach was taken using the Capability-Opportunity-Motivation-Behaviour (COM-B) model and Behaviour Change Wheel (BCW) framework. The key determinants of energy balance in the early years were identified from the Foresight Systems Map. Policy actions were scoped systematically from available literature, including any health or non-health policies which could impact on energy balance behaviours. Foresight variables and policy actions were considered in terms of COM-B and the BCW to determine approaches likely to be effective for obesity prevention and treatment. Existing policies were overlaid across the map of key risk factors to identify gaps in obesity prevention and treatment provision. Results A wide range of policy actions were identified (n=115) to address obesity-relevant risk factors. These were most commonly educational or guidelines relating to environmental restructuring (i.e. changing the physical or social context). Scope for strengthening policies relating to the food system (e.g. the market price of food) and psychological factors contributing to obesity were identified. Policies acted via all aspects of the COM-B model, but there was scope for improving policies to increase capability through skills acquisition and both reflective and automatic motivation. Conclusions There is substantial policy activity to address early years obesity but much is focused on education. Scope exists to strengthen actions relating to upstream policies which act on food systems and those targeting psychological factors contributing to obesity risk

Clinical components and associated behavioural aspects of a complex healthcare intervention : Multi-methods study of selective decontamination of the digestive tract in critical care

Copyright © 2013 Australian College of Critical Care Nurses Ltd. Published by Elsevier Ltd. All rights reserved.Peer reviewedPostprin

Anisotropic static solutions in modelling highly compact bodies

Einstein field equations for anisotropic spheres are solved and exact interior solutions obtained. This paper extends earlier treatments to include anisotropic models which accommodate a wider variety of physically viable energy densities. Two classes of solutions are possible. The first class contains the limiting case $\mu\propto r^{-2}$ for the energy density which arises in many astrophysical applications. In the second class the singularity at the center of the star is not present in the energy density. The models presented in this paper allow for increasing and decreasing profiles in the behavior of the energy density.Comment: 9 pages, to appear in Pramana - J. Phy

Compact anisotropic spheres with prescribed energy density

New exact interior solutions to the Einstein field equations for anisotropic spheres are found. We utilise a procedure that necessitates a choice for the energy density and the radial pressure. This class contains the constant density model of Maharaj and Maartens (Gen. Rel. Grav., Vol 21, 899-905, 1989) and the variable density model of Gokhroo and Mehra (Gen. Rel. Grav., Vol 26, 75-84, 1994) as special cases. These anisotropic spheres match smoothly to the Schwarzschild exterior and gravitational potentials are well behaved in the interior. A graphical analysis of the matter variables is performed which points to a physically reasonable matter distribution.Comment: 22 pages, 3 figures, to appear in Gen. Rel. Gra

Participation in physical play and leisure : developing a theory- and evidence-based intervention for children with motor impairments

Peer reviewedPublisher PD

Structural, item, and test generalizability of the psychopathology checklist - revised to offenders with intellectual disabilities

The Psychopathy Checklist–Revised (PCL-R) is the most widely used measure of psychopathy in forensic clinical practice, but the generalizability of the measure to offenders with intellectual disabilities (ID) has not been clearly established. This study examined the structural equivalence and scalar equivalence of the PCL-R in a sample of 185 male offenders with ID in forensic mental health settings, as compared with a sample of 1,212 male prisoners without ID. Three models of the PCL-R’s factor structure were evaluated with confirmatory factor analysis. The 3-factor hierarchical model of psychopathy was found to be a good fit to the ID PCL-R data, whereas neither the 4-factor model nor the traditional 2-factor model fitted. There were no cross-group differences in the factor structure, providing evidence of structural equivalence. However, item response theory analyses indicated metric differences in the ratings of psychopathy symptoms between the ID group and the comparison prisoner group. This finding has potential implications for the interpretation of PCL-R scores obtained with people with ID in forensic psychiatric settings